Expansible plug.



YPATEITI'ID APR. 18, 1905.

C. D. MOSHER.

EXPANSIBLE PLUG. APPLIOATION FILED 00T.2,1903.

Ina/enor:

f/ Mobiler,

UNITED STaTEs Patented April 1s, 1905.

PATENT EEicE- A(JHARLES D. MOSHER, OF 'NEW YCRK, N. Y.

ExPANsiBLE PLUG.

SPECIFICATION forming` part of Letters Patent No. '787.460, dated April 18, 1905. Application filed Gctoher 2, 1903. Serial No. 175,476.

. citizen of the United States, residing at New York, in the county of New -York and State ot' New York, have invented certain new and useful Improvements in Expansible Plugs, of

which the following' is a specification. v

My invention relates to plugs for boilers, condenseisand like structures where the metal forming the shell is too thin to permit them to be threaded and in cases where it is desirable and necessary to readily remove the plug.

'lhe invention has special reference to plugs which are expanded into place; and the object is to construct a plug which will more readily yield to the expanding-tool and when expanded will be firmly seated on the rim of the hole, as will now be set forth more` fully. i

In the drawings, Figure 1 is a cross-section of the shell of a boiler and a plug resting therein preparatory to expanding same. l Fig.

2 is a cross-section of the same, showing 'the plug expanded in position. Fig. 3 is a crosssection of a plug, showing an internal annular corrugation; and Fig. 4 is a cross-section of a plug which is provided with several annular corrugations. r

In preparing the shell 8 I form the hole 6 in the usual manner, with the corners chamfered away, as shown at 7. The plug 5 is stamped out of sheet metal, cup-shaped, as shown, with an exterior ange 9, the side`of the cup being tapered, as shown at 10, and the base ot' the cup is rounded or crowned, as at 11.

As illustrated in Fig. l, the side wall near the base has an annular bulging portion 12, which in practice extends out so that the diameter of this bulging portion is the exact diameter of the hole 6 in the shell 8, and it will be observed'that when the plug is in position the exterior diameter of the plug next to the iange 9 is also the diameter of the hole 6. Constructed in this manner'there is an intei-nal annular ridge or raised portion 13, which is substantially on the same plane as the inner edge of the shell 8, so that when the expanding-tool is applied to this ridge and forced outwardly the shell of the plug will more-readily yield than otherwise and cause the exterior body of the plug to seat itself against theinner rim of the hole, as shown in Fig. 2.

I may modify somewhat the structural Jformation, particularly so far asconcerns the relative location of the interior ridge; but the essential features of the invention relate to the slightly-tapering cup-shaped plug and to the exterior annular bulging portion of the base, together with the internal ridge to serve as a bearing-point for the expander when in use.-

It is not material whether the annular corrugations project externally, as inFig. 1, or internally, as in Fig. 3. The latter form has some advantages in point of construction, par- `ticularly where the plugs are made ot' thick It will be noted that the side wall material. 14 need not be tapered, as in Fig. 1; butin such case I prefer to make a pronounced in- -ternal annular corrugation 15,'against which the expanding-tool acts during the process of expanding.

In Fig. 4 I provide a single internal corrugation 16, and two external annular'corrugations 17 18, as thereby the bodyvof the cup or plug will the more readily yield to the action of the expander, as well as to permit me to make the plug of heavy metal.

Nhat I'claim as new isv 'A 1. A cup-shaped expansible plug provided with an annular interior bulging portion near its base, in combination with a shell having a hole therein and adapted to receive said plug.

2. A cup-shaped expansibleplug having tapering sides and provided with'an interior annular bulging portion near its base, in combination with a shell having a hole therein and adapted to receive said plug.

3. A hollow or cup-shaped expansible plug having corrugations near its inner end.

4. A hollow or cup-shaped expansible plug having corrugations near its inner end, in combination with a shell having a hole .in'which said plug is expanded.

' 5. A hollow or cup-shaped plug with tapering sides and corrugations at its inner end, in

combination with a shell having a llole there- J. S. ZERBE, B. BARINE. 

